<?php

if ( ! defined( 'ABSPATH' ) ) {
	exit;
}

class MFP_Taxonomy {

	public const TAXONOMY = 'media_folder';

	public function register(): void {
		register_taxonomy( self::TAXONOMY, 'attachment', [
			'labels'            => [
				'name'          => __( 'Foldery mediów', 'media-folder-pro' ),
				'singular_name' => __( 'Folder mediów', 'media-folder-pro' ),
				'add_new_item'  => __( 'Dodaj nowy folder', 'media-folder-pro' ),
				'edit_item'     => __( 'Edytuj folder', 'media-folder-pro' ),
			],
			'hierarchical'      => true,
			'public'            => false,
			'show_ui'           => false,
			'show_in_rest'      => true,
			'show_admin_column' => false,
			'query_var'         => false,
			'rewrite'           => false,
		] );
	}

	/**
	 * @return array<int, array{id: int, name: string, slug: string, parent: int, count: int, children: array}>
	 */
	public function get_folder_tree(): array {
		$terms = get_terms( [
			'taxonomy'   => self::TAXONOMY,
			'hide_empty' => false,
			'orderby'    => 'name',
			'order'      => 'ASC',
		] );

		if ( is_wp_error( $terms ) || empty( $terms ) ) {
			return [];
		}

		$flat = [];
		foreach ( $terms as $term ) {
			$flat[ $term->term_id ] = [
				'id'       => $term->term_id,
				'name'     => $term->name,
				'slug'     => $term->slug,
				'parent'   => $term->parent,
				'count'    => (int) $term->count,
				'children' => [],
			];
		}

		$tree = [];
		foreach ( $flat as $id => &$node ) {
			if ( $node['parent'] === 0 ) {
				$tree[] = &$flat[ $id ];
			} elseif ( isset( $flat[ $node['parent'] ] ) ) {
				$flat[ $node['parent'] ]['children'][] = &$flat[ $id ];
			} else {
				$tree[] = &$flat[ $id ];
			}
		}
		unset( $node );

		return $tree;
	}

	public function folder_has_children( int $folder_id ): bool {
		$children = get_terms( [
			'taxonomy'   => self::TAXONOMY,
			'parent'     => $folder_id,
			'hide_empty' => false,
			'number'     => 1,
			'fields'     => 'ids',
		] );

		if ( ! empty( $children ) ) {
			return true;
		}

		$attachments = get_posts( [
			'post_type'      => 'attachment',
			'post_status'    => 'inherit',
			'tax_query'      => [
				[
					'taxonomy' => self::TAXONOMY,
					'terms'    => $folder_id,
				],
			],
			'posts_per_page' => 1,
			'fields'         => 'ids',
		] );

		return ! empty( $attachments );
	}

	public function would_create_cycle( int $folder_id, int $new_parent_id ): bool {
		if ( $new_parent_id === 0 ) {
			return false;
		}
		if ( $folder_id === $new_parent_id ) {
			return true;
		}

		$current = $new_parent_id;
		while ( $current !== 0 ) {
			$term = get_term( $current, self::TAXONOMY );
			if ( is_wp_error( $term ) || ! $term ) {
				break;
			}
			if ( $term->parent === $folder_id ) {
				return true;
			}
			$current = $term->parent;
		}

		return false;
	}
}